Tuesday, November 25, 2008

GSS Wordsum proxy for IQ, not definitive measure of it

In several recent posts, I've used the GSS' data on Wordsum scores to estimate IQ for various things. Steve Sailer admonishes me to be cautious in relying on the quick vocabularly test as an accurate measure of intelligence:

Do you have a sense for how much the GSS needs to be orrected for the fact that it's not a full IQ test, it's just a 10 question vocabulary test? Yes, I know vocabulary correlates with g, the general factor, to a high degree, but I'm concerned that an over-reliance on vocabulary misses out on important non-g subfactors in intelligence, especially 3-dimensional processing power. One's ability to accurately rotate 3-d objects in one's imagination is fairly separate from g, but it's not unimportant in overall IQ. And, it's clearly related in some fashion to masculinity, since men average something like 3/4ths of a standard deviation higher on it.

This probably isn't worth worrying about for most uses of the GSS vocabulary scores, but for something like propensity to go hunting, which no doubt is related in some fashion to male hormone levels, it does seem important.

The difference between the GSS vocabulary test and a true IQ test is probably also important for politics, too. My impression is that colleges where students average higher on the SAT Math than on the SAT Verbal tend to be more conservative than mirror image schools of the same overall SAT score. That at least was my experience at Rice in the late 1970s.

The only thing I can think to do is to separate Wordsum results by gender and create IQ conversions for men and women based on their respective score distributions, since female average scores are about .1 standard deviation higher than male scores are.

To specifically address the hunting issue, consider just the estimates for white women who do not hunt but who have a spouse who does (98.9) and white women who do not hunt nor have a spouse who hunts (100.2). Hunting still appears to be an activity of the modestly less intelligent among whites.

Steve's comments provide an appropriate opportunity to remind readers that the GSS provides us with suggestive trends, not definitive ones. The Wordsum test surely correlates with IQ, but it's a proxy measure, not an exact one (a regional comparison of Wordsum averages and a host of other good faith IQ estimates confirms this). To avoid repetitive verbiage, I won't point as much out in every post relying on GSS data going forward, but it is important to be aware of.

Yes I tried. :) But, the words just don't do as well in my head as the numbers.

I don't think I am that out of the ordinary though. Take a look at this chart of PhD GRE scores. Most of those getting math heavy degrees score 170+ higher on quantitative than verbal.

AE,

Yes, I figure that my result is my no means standard for the population at large. But, I still won't support a IQ system that discriminates against my people (that being those with small vocabularies and very strong number skills). :)

Hehe, I mean no harm, honest! I've looked at hunting and two other reasonable IQ proxies (upcoming post)--educational attainment and income--and remain confident that hunting is, among whites, an activity associated with moderately lower average intelligence.

Fortunately for me, many of my neighbors are outdoorsy types, proficient with firearms and mechanically competent. I am neither, but at least I'll have friends to help me out. Presumably I'll have to really break my back to make up for my general uselessness.